This randomized controlled comparison of the safety and efficacy of RS-79070, an oral pro-drug of ganciclovir with IV ganciclovir as induction therapy for the treatment of newly diagnosed peripheral CMV retinitis. Further objectives are to assess the effects of both induction and maintenance therapy with RS-79070 on CMV viral load, and to assess the pharmacokinetics of ganciclovir following administration of RS-79070. Patients will be randomly assigned to receive either IV ganciclovir at 5 mg/kg IV bid for 3 weeks, then IV ganciclovir 5mg/kg qd for one week. The other group will receive the investigational therapy of 900 mg of RS-79070 po bid for 3 weeks, followed by 900 mg of RS-79070 qd for one week. Following this phase of the trial, all patients will be offered entry into a long-term follow-up phase of the study where they can receive 900 mg of RS-79070 po qd.